Replication of low-level carcinogenic activity bioassays.

Bioassay for carcinogenic activity of a number of epoxides, lactones, hydroperoxides, and peroxides was reported from the laboratory at New York University (2,3). The compounds were tested by skin application on mice, s.c. injection in mice and rats, and feeding and intratracheal instillation in rats. Another series of related compounds was more recently tested at Fels Research Institute by s.c. injection in mice (1). Included in this series were compounds such as stearic acid and 7-stearolactone which, on the basis of known structurebiological activity relationships and the known occurrence Five compounds were selected: stearic acid, methyl stéarate, 7-stearolactone, p-nitroperbenzoic acid, and glycidyl stéarate. The same chemical samples and the same batch of tricaprylin as vehicle were used in both laboratories. The chemicals were given s.c. to mice once weekly for 26 weeks. The conditions of the experiments, as described in the full reports (1,3) were as identical as possible. The only known difference was that the New York University experiments were with ICR/Ha Swiss Millerton female mice, whereas the Fels experiments used CFW (Swiss Webster) female mice.